DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Geographic (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Number of segments | segment	1
Revenue recognition	$ 216,136	$ 208,475	$ 206,547
Property and equipment, net	52,671	41,269
United States [Member]
Revenue recognition	211,893	202,881	199,663
Property and equipment, net	38,564	26,960
Canada [Member]
Revenue recognition	4,243	5,594	$ 6,884
Property and equipment, net	13,831	$ 14,309
INDIA
Property and equipment, net	$ 276